Classification Of Drugs According To Pharmacological Effect

A drug is a chemical substance which is characterized by a defined chemical, physical and biological properties, any slight change in its chemical structure can cause great change in the host’s body and can cause maybe desired or undesired effects. It aims for treating, curing diseases and illuminating its symptoms by an exact mechanism that differs from drug to another according to the drug’s therapeutic effect, time taken by a drug to perform its action and the disease needed to be illuminated. Drug is related to pharmacy which is a Greek word ‘pharmakon’, which means (medicine or drug). It is formulated by means of chemists or pharmacists who can deal with drugs and form formulas that has no side effects and cause no adverse reaction that can cause harm to the host so they are responsible for monitoring the patient’s health.

Drugs are always formulated in form of a dosage form, mixed with excipients, which gives the drug its stability and its unique shape. Dosage form is the carrier of drug which carry drug to its site of action in the body, which allow safe transfer of exact amount of drug to the place required to perform its function. Each drug has its own monograph which is the descriptive material of this drug. This monograph is listed in pharmacopoeia which is a legal authority for standardization of this drug. Drugs maybe from natural sources or synthetic ones. They are found in various forms as tablets, capsules, syrup, injections. This variety in forms of drug aims to suit the patient’s need and the condition of each patient. For example if a person suffers from vomiting he can’t take either tablets or capsules, but he can take injections.

Drugs are almost grouped and classified. This classification can be according to their pharmacological effect, their chemical activity, their names, or the conditions they cure. The most common classifications is according to their pharmacological effect on both human and animals.

There are many types of drugs that differ in their way of treatment, and the effect they cause, from these drugs are:

1. Depressants: Drugs taken to relieve anxiety and control sleeping. They act on central nervous system to slow down brain’s activity. It leads to drop in blood pressure and can cause psychological problems. E.g., thiopental, cannabis.
2. Inhalants: Taken among inhalation, it can be misused by children and adolescent as it may exist as vapors or housing items, after first inhaling symptoms appear which maybe vomiting, nausea, headache. E.g., gasoline or pen ink. Chemotherapeutic drugs: Drugs attack specific organisms that cause certain disease and act to illuminate this disease without harming the host. E.g., cancer disease.
3. Pharmacodynamics drugs: Drugs that affect cell activity by stimulating and increasing its activity, or by suppressing and depressing its action. E.g., inverse agonist.
4. Stimulants: Drugs that can cause both desired and undesired moods. It can affect attention, focusing and coordination; also it can lead to anger, and feeling paranoid at same time. The greater consumption the greater the risk will be. E.g., drugs as cocaine, alcohols, and amphetamine which causes physical disorders.

The pharmacological effect of any drug is based on an onset time. This time at which the drug’s concentration in the body of the patient becomes above the minimum effective concentration, so that the drug starts its therapeutic effect, and becomes able to compact a specific disease. This onset time differs from a drug to another according to routes of administration. E.g., the oral route takes about 30 – 90 minutes till time of action, while the intravenous route takes about 30 – 60 seconds till time of action.

So the patient must be aware of this onset time, and make sure he is taking the right medication by the correct dosing in the right time to ensure that the drug will form its therapeutic effect accurately. Drugs can cause either systemic or local effect or can cause both effects according to the route of administration. E.g., Topical route for drugs can form local effect only as it is not absorbed in blood stream as anti-inflammatory drugs, while oral route for drugs can cause systemic effect when it is absorbed by gastro intestinal tracts and it can also give a local effect as antacid or antihypertensive drugs.

Antihypertensive drugs: Class of drugs which control and treat high blood pressure which occur due to fast blood pumping through arteries, it usually occurs after exercising or under stress where blood pushes through walls of artery and its pressure increase, antihypertensive decrease blood pressure to normal level. E.g., Diuretics. Although drugs have therapeutic effect, they can also cause unwanted side effects as in the following cases:

First the increase in drug concentration in patient’s body above the maximum effective concentration, this can cause side effects, It can occur due to drug misuse (taking drugs in a wrong way unintentionally) or drug abuse (taking drugs in a wrong way intentionally E.g., painkillers and cough syrups rather than killing pain and treating cough), taking more than the prescript amount without a doctor’s consultation or without doctor’s order, taking prescript drugs in wrong periods of time than the correct ones.

This can lead to undesired effects, as unwanted physical and mental effect, it can alter your mood and increase anxiety. The person may become addicted unintentionally as the person’s metabolism cannot detoxify the drug fast enough to avoid its side effects, his body becomes tolerant to different types of drugs and sensitive to different medications, so it needs rather large amounts of drugs to perform normally with its normal action. So that drugs are classified into prescription drugs and none prescription drugs.

Prescription drugs: Drugs which are only used under a doctor’s supervision, they are not used for self- treatment, if misused it can cause an adverse reaction on the host’s body so it can’t be safely used without supervision from a specialist. E.g., Generic Norvasc.

None prescription drugs: Drugs taken without doctor’s supervision, they are sold legally in pharmacies, they can be used safely for self- treatment and cause no side effects. These classifications aim to classify drugs according to legal and illegal drugs, drugs with adverse action and safe drugs.